/*
 * Tencent is pleased to support the open source community by making Angel available.
 *
 * Copyright (C) 2017-2018 THL A29 Limited, a Tencent company. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 *
 * https://opensource.org/licenses/Apache-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 *
 */
package com.tencent.angel.sona.psf

import com.tencent.angel.ml.matrix.psf.aggr.enhance.UnaryAggrFunc
import com.tencent.angel.ps.storage.vector.{ServerRow, ServerRowUtils}

class StatsFunc(matrixId: Int) extends UnaryAggrFunc(matrixId, 0) {

  def this() = { this(-1) }

  override protected def mergeInit: Double = 0.0

  override protected def mergeOp(a: Double, b: Double): Double = {
    a + b
  }

  override protected def processRow(row: ServerRow): Double = {
    ServerRowUtils.getVector(row).getSize
  }
}
